Digital images can be manipulated in a variety of ways while maintaining their content. There are a number of applications where it is important to be able to determine if a particular image may have been manipulated from a source image.
As examples, a source image may have been manipulated by any combination of rescaling, distortion, warping, skewing, cropping, rotation, mirroring, recoloring, the addition of text or watermark, steganography, noise addition, image format changes, or image metadata changes. Some typical applications where there is a need to determine if a source image has been manipulated include copyright enforcement and image forensics.